Various rotary electric machines as, for example, so-called brushless alternators, require the use of rotating rectifier assemblies. In order to avoid the use of brushes, the magnetic field required to induce current is generated by passing a direct current through windings carried by the rotor of the machine. This, in turn, requires that the direct current provided to the rotor field winding be derived from electrical components forming part of the rotor, again to avoid any need for brushes.
Typically, the rotor will carry a series of permanent magnets such that when the rotor is rotated, the magnets will induce an electrical current in a fixed winding forming part of the alternator. These components constitute a conventional permanent magnet generator.
The current induced in the permanent magnet generator is, in turn, rectified and regulated and fed to a so-called exciter. The exciter, in turn, induces an alternating current in a winding, usually a three phase winding, carried by the rotor. The resulting three phase signal is then inputted to a three phase, full wave rectifier which in turn provides the direct current input to the rotor field windings.
In many instances, as, for example, in aircraft generating systems, in addition to the usual reliability concerns, size and weight restrictions are significant. The compactness, or lack thereof, of the rotor will dictate certain bearing and housing size selections and thus affect the weight of the system. And, of course, since the rotating rectifier assembly forms part of the rotor and therefore influences its size, every effort is made to minimize its size and weight.
Prior art of possible relevance includes the following U.S. Pat. No. 3,160,771 issued Dec. 8, 1964 to Martin; U.S. Pat. No. 3,470,405 issued Sept. 30, 1969 to Andersson; and U.S. Pat. No. 4,052,631 issued Oct. 4, 1977 to Kuter. Frequently, the prior art approaches as exemplified by the foregoing may generate axially compact rectifier assemblies but only at the expense of increased radial size. Martin is representative of this downfall.
In other cases, radial compactness is achieved but at the expense of an increase in axial size. Andersson is representative of this downfall. In other cases, such difficulties are compounded by the use of plural clamps for assuring good electrical contact amongst the components of the rectifier assembly and/or proper cooling which may increase both size and weight as, for example, shown in Kuter.
The present invention is directed to overcoming one or more of the above problems.